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<title>Debugging with GDB: Progspaces In Python</title>

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<a name="Progspaces-In-Python"></a>
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<a name="Program-Spaces-In-Python"></a>
<h4 class="subsubsection">23.2.2.22 Program Spaces In Python</h4>

<a name="index-progspaces-in-python"></a>
<a name="index-gdb_002eProgspace"></a>
<a name="index-Progspace"></a>
<p>A program space, or <em>progspace</em>, represents a symbolic view
of an address space.
It consists of all of the objfiles of the program.
See <a href="Objfiles-In-Python.html#Objfiles-In-Python">Objfiles In Python</a>.
See <a href="Inferiors-and-Programs.html#Inferiors-and-Programs">program spaces</a>, for more details
about program spaces.
</p>
<p>The following progspace-related functions are available in the
<code>gdb</code> module:
</p>
<a name="index-gdb_002ecurrent_005fprogspace"></a>
<dl>
<dt><a name="index-gdb_002ecurrent_005fprogspace-1"></a>Function: <strong>gdb.current_progspace</strong> <em>()</em></dt>
<dd><p>This function returns the program space of the currently selected inferior.
See <a href="Inferiors-and-Programs.html#Inferiors-and-Programs">Inferiors and Programs</a>.
</p></dd></dl>

<a name="index-gdb_002eprogspaces"></a>
<dl>
<dt><a name="index-gdb_002eprogspaces-1"></a>Function: <strong>gdb.progspaces</strong> <em>()</em></dt>
<dd><p>Return a sequence of all the progspaces currently known to <small>GDB</small>.
</p></dd></dl>

<p>Each progspace is represented by an instance of the <code>gdb.Progspace</code>
class.
</p>
<dl>
<dt><a name="index-Progspace_002efilename"></a>Variable: <strong>Progspace.filename</strong></dt>
<dd><p>The file name of the progspace as a string.
</p></dd></dl>

<dl>
<dt><a name="index-Progspace_002epretty_005fprinters"></a>Variable: <strong>Progspace.pretty_printers</strong></dt>
<dd><p>The <code>pretty_printers</code> attribute is a list of functions.  It is
used to look up pretty-printers.  A <code>Value</code> is passed to each
function in order; if the function returns <code>None</code>, then the
search continues.  Otherwise, the return value should be an object
which is used to format the value.  See <a href="Pretty-Printing-API.html#Pretty-Printing-API">Pretty Printing API</a>, for more
information.
</p></dd></dl>

<dl>
<dt><a name="index-Progspace_002etype_005fprinters"></a>Variable: <strong>Progspace.type_printers</strong></dt>
<dd><p>The <code>type_printers</code> attribute is a list of type printer objects.
See <a href="Type-Printing-API.html#Type-Printing-API">Type Printing API</a>, for more information.
</p></dd></dl>

<dl>
<dt><a name="index-Progspace_002eframe_005ffilters"></a>Variable: <strong>Progspace.frame_filters</strong></dt>
<dd><p>The <code>frame_filters</code> attribute is a dictionary of frame filter
objects.  See <a href="Frame-Filter-API.html#Frame-Filter-API">Frame Filter API</a>, for more information.
</p></dd></dl>

<p>One may add arbitrary attributes to <code>gdb.Progspace</code> objects
in the usual Python way.
This is useful if, for example, one needs to do some extra record keeping
associated with the program space.
</p>
<p>In this contrived example, we want to perform some processing when
an objfile with a certain symbol is loaded, but we only want to do
this once because it is expensive.  To achieve this we record the results
with the program space because we can&rsquo;t predict when the desired objfile
will be loaded.
</p>
<div class="smallexample">
<pre class="smallexample">(gdb) python
def clear_objfiles_handler(event):
    event.progspace.expensive_computation = None
def expensive(symbol):
    &quot;&quot;&quot;A mock routine to perform an &quot;expensive&quot; computation on symbol.&quot;&quot;&quot;
    print &quot;Computing the answer to the ultimate question ...&quot;
    return 42
def new_objfile_handler(event):
    objfile = event.new_objfile
    progspace = objfile.progspace
    if not hasattr(progspace, 'expensive_computation') or \
            progspace.expensive_computation is None:
        # We use 'main' for the symbol to keep the example simple.
        # Note: There's no current way to constrain the lookup
        # to one objfile.
        symbol = gdb.lookup_global_symbol('main')
        if symbol is not None:
            progspace.expensive_computation = expensive(symbol)
gdb.events.clear_objfiles.connect(clear_objfiles_handler)
gdb.events.new_objfile.connect(new_objfile_handler)
end
(gdb) file /tmp/hello
Reading symbols from /tmp/hello...done.
Computing the answer to the ultimate question ...
(gdb) python print gdb.current_progspace().expensive_computation
42
(gdb) run
Starting program: /tmp/hello
Hello.
[Inferior 1 (process 4242) exited normally]
</pre></div>

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Next: <a href="Objfiles-In-Python.html#Objfiles-In-Python" accesskey="n" rel="next">Objfiles In Python</a>, Previous: <a href="Functions-In-Python.html#Functions-In-Python" accesskey="p" rel="prev">Functions In Python</a>, Up: <a href="Python-API.html#Python-API" accesskey="u" rel="up">Python API</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
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